The invention relates to pump seals, and more particularly to a static seal arrangement for centrifugal pumps with dynamic seal arrangements.
Arrangements of flexible face seals are known from U.S. Pat. Nos. 3,713,659; 3,504,917; 4,311,315; and 3,016,251. These seal arrangements are designed to seal at relatively low pressures, so that at pressures higher than 20 psi, the flexible lip is easily damaged with resultant leakage.
U.S. Pat. No. 4,186,929 shows another type arrangement with a conventional lip seal, a non-flexible washer, and a flexible member. The conventional lip seal requires lubrication, and the flexible members run with a relatively big axial gap. At static conditions, the axial gap will get packed with contaminants. When pressure occurs, it forces contaminants into the lip seal area. In addition, the flexible member does not perform effectively because of the axial gap.
Other seal arrangements showing the state of the art are U.S. Pat. Nos. 623,127; 3,284,145; 3,588,129; and 4,509,773. Various face seal arrangements of the prior art are shown in U.S. Pat. Nos. 3,207,521; 3,771,799; 4,186,929; 2,368,137; 2,990,220; 3,612,547; and 3,727,923.
The tandem mounted face seals are an advance over the prior art arrangements represented above, and provide a novel solution to overcome severe application problems where high static or dynamic pressure occurs.